Re: [PATCH 3/5] hw/core: Remove uses of QERR_DEVICE_NO_HOTPLUG

[Damien Hedde]

On 11/19/21 09:20, Markus Armbruster wrote:
> Philippe Mathieu-Daudé <philmd@redhat.com> writes:
>
> > QERR_DEVICE_NO_HOTPLUG definition is obsolete since 2015 (commit
> > 4629ed1e989, "qerror: Finally unused, clean up"). Replace the two
> > uses and drop the definition.
> >
> > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> > ---
> >   include/qapi/qmp/qerror.h | 3 ---
> >   hw/core/qdev.c            | 3 ++-
> >   softmmu/qdev-monitor.c    | 2 +-
> >   3 files changed, 3 insertions(+), 5 deletions(-)
> >
> > diff --git a/include/qapi/qmp/qerror.h b/include/qapi/qmp/qerror.h
> > index 596fce0c54e..f49ae01cdb0 100644
> > --- a/include/qapi/qmp/qerror.h
> > +++ b/include/qapi/qmp/qerror.h
> > @@ -26,9 +26,6 @@
> >   #define QERR_DEVICE_IN_USE \
> >       "Device '%s' is in use"
> >   
> > -#define QERR_DEVICE_NO_HOTPLUG \
> > -    "Device '%s' does not support hotplugging"
> > -
> >   #define QERR_FEATURE_DISABLED \
> >       "The feature '%s' is not enabled"
> >   
> > diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> > index 7f06403752d..14375861c36 100644
> > --- a/hw/core/qdev.c
> > +++ b/hw/core/qdev.c
> > @@ -734,7 +734,8 @@ static void device_set_realized(Object *obj, bool value, 
> > Error **errp)
> >       static int unattached_count;
> >   
> >       if (dev->hotplugged && !dc->hotpluggable) {
> > -        error_setg(errp, QERR_DEVICE_NO_HOTPLUG, object_get_typename(obj));
> > +        error_setg(errp, "Device '%s' does not support hotplugging",
> > +                   object_get_typename(obj));
> >           return;
> >       }
> >   
> > diff --git a/softmmu/qdev-monitor.c b/softmmu/qdev-monitor.c
> > index 4851de51a5c..35a885a6623 100644
> > --- a/softmmu/qdev-monitor.c
> > +++ b/softmmu/qdev-monitor.c
> > @@ -896,7 +896,7 @@ void qdev_unplug(DeviceState *dev, Error **errp)
> >       }
> >   
> >       if (!dc->hotpluggable) {
> > -        error_setg(errp, QERR_DEVICE_NO_HOTPLUG,
> > +        error_setg(errp, "Device '%s' does not support hotplugging",
> >                      object_get_typename(OBJECT(dev)));
> >           return;
> >       }
>
> When the same error is detected in multiple places, I like to ask myself
> whether the code calls for a refactoring.  But I can't see a useful one
> here.

Since the realize check will catch more case (devices created 
recursively by a command or simply by C code), we could remove the 
softmmu/qdev-monitor.c check and rely on realize catching that just after.
In theory failing during realize should have the same result as "not 
trying to create the device in the first place".

--
Damien